Expression of β-xylosidase An-xyl from Aspergillus niger and characterization of its xylose tolerance / 生物工程学报

The hydrolysis of xylo-oligosaccharides catalyzed by β-xylosidase plays an important role in the degradation of lignocellulose. However, the enzyme is easily inhibited by its catalytic product xylose, which severely limits its application. Based on molecular docking, this paper studied the xylose affinity of Aspergillus niger β-xylosidase An-xyl, which was significantly differentially expressed in the fermentation medium of tea stalks, through cloning, expression and characterization. The synergistic degradation effect of this enzyme and cellulase on lignocellulose in tea stems was investigated. Molecular docking showed that the affinity of An-xyl to xylose was lower than that of Aspergillus oryzae β-xylosidase with poor xylose tolerance. The Ki value of xylose inhibition constant of recombinant-expressed An-xyl was 433.2 mmol/L, higher than that of most β-xylosidases of the GH3 family. The Km and Vmax towards pNPX were 3.6 mmol/L and 10 000 μmol/(min·mL), respectively. The optimum temperature of An-xyl was 65 ℃, the optimum pH was 4.0, 61% of the An-xyl activity could be retained upon treatment at 65 ℃ for 300 min, and 80% of the An-xyl activity could be retained upon treatment at pH 2.0-8.0 for 24 h. The hydrolysis of tea stem by An-xyl and cellulase produced 19.3% and 38.6% higher reducing sugar content at 2 h and 4 h, respectively, than that of using cellulase alone. This study showed that the An-xyl mined from differential expression exhibited high xylose tolerance and higher catalytic activity and stability, and could hydrolyze tea stem lignocellulose synergistically, which enriched the resource of β-xylosidase with high xylose tolerance, thus may facilitate the advanced experimental research and its application.

Analysis of the clinical characteristics, long-term prognosis and changes of pulmonary function in children with idiopathic pulmonary fibrosis / 中华实用儿科临床杂志

Objective:To investigate the clinical characteristics, long-term prognosis and changes of pulmonary function in children with idiopathic pulmonary fibrosis (IPF).Methods:The clinical data, long-term prognosis and changes of pulmonary function of children with IPF admitted to the Department of Pediatric Respiratory Center in Children′s Hospital of Chongqing Medical University from January 2008 to December 2018 were retrospectively analyzed.Results:A total of 28 cases were included, with the median age of 3.9 years (range: 0.5 to 15.7 years). Cough (28 cases, 100.0%), tachypnea (25 cases, 89.3%), cyanosis (19 cases, 67.9%), dyspnea (11 cases, 39.3%), Velcho rales (12 cases, 42.9%), inspiratory three concave sign (11 cases, 39.3%), clubbed fingers and toes (6 cases, 21.4%) and diminished breath sounds (5 cases, 17.9%) were main clinical manifestations.Chest high-resolution computed tomography (HRCT) mainly displayed grid shadow, irregular sac-like light-transparent shadow with ho-neycomb changes and dense shadow, partial (7 cases) pulmonary interstitial emphysema/emphysema/pneumomediastinum.Three cases of lung biopsy showed hyperplasia and consolidation of alveolar space and alveolar septal fibrosis, thickening of alveolar wall and coexistence of new and old lesions.In this group, 4 cases did not receive drug therapy due to other reasons (3 cases abandoned therapy, and 1case died of respiratory and circulatory failure during hospitalization). Twenty-four cases were treated with single or combination of oral Prednisone, N-acetylcysteine and Azithromycin.Eleven cases had improved symptoms when discharged, and 13 cases showed no improvement.Twenty-four cases continued to receive oral medication therapy according to the original protocol.Eight cases were followed up for chest HRCT for 3 months to 4 years, the chest HRCT lesions of 7 cases were similar to before, and those of 1 case increased than before.All cases received telephone follow-up for 2 to 7 years; the maximum duration of medication was 4 years.Twelve cases were lost to follow-up, 7 cases had motion limitation, 3 cases died, and 2 cases had no clinical symptom.Three cases were followed up for pulmonary function for 2 to 3 years, among which 2 cases had pulmonary function decreased than before; 1 case had improvements in forced vital capacity as a percentage of the predicted value and peak expiratory flow as a percentage of the predicted value, but decline in forced expiratory volume in the first se-cond as a percentage of the predicted value.Conclusions:The clinical manifestations of children with IPF are lack of specificity.Chest HRCT is of great value in the diagnosis of IPF and preliminary monitoring of the activity of lesion.In the long-term follow-up, some of cases have improvements in symptoms; pulmonary function mostly decreases, but part of indexes can be improved.

Optimization of the Extraction Technology of Phenolic Acid from Amomum tsaoko / 中国药房

OBJECTIVE：To opt imize the extraction technology of phenolic acid from Amomum tsaoko . METHODS ：The extraction technology of phenolic acid from A. tsaoko was optimized by using Box-Behnken design-response surface methodology with ethanol volume fraction ，liquid-solid ratio and extraction time as factors ，using the total contents of protocatechuic acid and vanillic acid as response value. The optimizd extraction technology was vlidated. RESULTS ：The optimal extraction technology was as follows ：ethanol volume fraction 65％，liquid-solid ratio 4∶1（mL/g），extraction time 2.5 h. After 3 times of validation tests ， average total content of protocatechuic acid and vanillic acid were 12.32 mg/g（RSD＝0.26 ％，n＝3），average relative error of which with predicted value （12.63 mg/g）was 2.45％. CONCLUSIONS ：The optimal technology is stable and feasible .

Use of Psychotropic Substances in Outpatients of Our Hospital / 中国药房

OBJECTIVE: To investigate the use of psychotropic substances for outpatients in our hospital.METHODS: The psychiatric substances used in the outpatients between June and December in 2006 were analyzed statistically in respect of the defined daily dose,DDDs and average daily expense etc.RESULTS: Of the total 7 286 prescriptions analyzed,the psychotropic substances prescribed totaled 12 kinds,of which,2 were typeⅠ,and 10 type Ⅱ.Estazolam,Alprazolam and Diazepam ranked at the first three places in terms of numbers of prescriptions;Estazolam,Alprazolam and Clonazepam ranked at the first three places in terms of DDDs;Zolpidem,Midazolam and Alprazolam ranked at the first three places in terms of consumption sum;Nitrazepam,Estazolam and Phenobarbital ranked at the lowest places in terms of average daily expense.CONCLUSION: Of the total psychiatric substances consumed in the outpatients of our hospital,benzodiazepines were used predominantly for their merits of low cost but proved efficacy.